export const file_exist = function (file_address = "", suffix = "") {
    
    let xmlhttp;    
    let yourFileURL;
    
    if(window.XMLHttpRequest) {    
        xmlhttp = new XMLHttpRequest();//其他浏览器    
    } else if (window.ActiveXObject) {    
        try {    
            xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");//旧版IE    
        } catch (e) { }  
    
        try {    
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");//新版IE    
        } catch (e) { } 
    
        if (!xmlhttp) {    
            window.alert("不能创建XMLHttpRequest对象");    
        }    
    }    
    
    yourFileURL = file_address;
    
    xmlhttp.open("GET", yourFileURL, false);  
    xmlhttp.send();  
    
    if(xmlhttp.readyState==4){     
        if(xmlhttp.status==200)   
            return true;     
        else 
            return false;   
    }  
}
